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Received: from authenticated-user by stravinsky.debian.org with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.96) (envelope-from ) id 1xNprd-0066zW-2N; Mon, 02 Nov 2026 11:06:09 +0000 Date: Mon, 2 Nov 2026 03:06:05 -0800 From: Breno Leitao To: Andrew Morton Cc: Catalin Marinas , David Hildenbrand , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH v2] mm: kmemleak: scan modified objects as soon as they are grayed Message-ID: References: <20261030-kmemleak-gray-drain-v2-1-3ec29a96668e@debian.org> <20261030120625.c2aa64b3e6378a2e78f2f676@linux-foundation.org> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261030120625.c2aa64b3e6378a2e78f2f676@linux-foundation.org> X-Debian-User: leitao X-Stat-Signature: qk1ixetdph4y98khbyyy13dmo9h4on3a X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=no autolearn_force=no version=4.0.1 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: BD8BD40003 X-Rspam-User: X-HE-Tag: 1793617575-199436 X-HE-Meta: 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 o04uysQg 1NAwk4iWSIkaZKPvTFkASlqxiXXTVkDG0gMbdUDpEB7wt4B642TO+E0LrZacdkAoK5MS1+YEvh9Po/KKbQN48Ib6+31+6Z04tMbPkzPxt5hIMYQ8hi1r/ELammxNPMH+HDYnuOAyO9A685zlHQSucESZssOi7w2uq8SSeBUkmcDrdrDvdnE+K1gv30h/CuER+PcZLaya6u23YDzG4qThZ7rZU6HvD/t6f2OIwN/gLqRh6Y2Z4tfaFDL33t7SZ2q6O/BpiKtHkQ5Pt66P+Tx2y7j3UWG61L0pvnqGJ77qdXCVN+Ic= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 Hello Andrew, On Fri, Oct 30, 2026 at 12:06:25PM -0700, Andrew Morton wrote: > On Fri, 30 Oct 2026 11:31:10 -0700 Breno Leitao wrote: > > > > Scanning the gray list after every grayed object made a full scan 41% > > slower (1.72s -> 2.42s, arm64 guest with lockdep) when the pass grays a > > million objects that do not point to each other. Scanning it at most > > once a jiffy keeps that at the baseline, leaves idle, file storm and > > mmap churn workloads unchanged, and still removes the false positives > > at HZ=100. > > Thanks. I'm thinking > > Fixes: 04609ccc40c4 ("kmemleak: Reduce the false positives by checking for modified objects") > cc:stable > > Agreed? Maybe, I think this is a another new way to fix false positives rather than a issue/bug fix itself, so, I would keep the Fixes:/Stable: tags out of this one. Thanks for asking, --breno